The Research Of C Band Low Spurious And Low Phase Noise Agility Frequency-hopping Frequency Synthesizer

Frequency synthesizer is a key part in modern communication systemsandelectronic systems, itsgood or bad performance directly determine the performance ofthese systems. With the continuous development of science and technology, the scholarsall over the worldpay more and more attention to high performance frequencysynthesizer.therefore, many researchs in diffrent countries have done a lot of research intheory and new technology of high performance frequency synthesizer, finally aftercontinuous efforts, has made great achievements. At present, all kinds of differentstructure, type and high performance frequency synthesizer has been developed; thesedifferent kinds of frequency synthesizer have been used in different fields.This paper introduces the basic theory of frequency synthesizer, development andresearch status at home and abroad; introduces and analyzes several method offrequency synthesizer with advantages and disadvantages, according to the needs of theproject,we designed high speed hopping signal and pulse FMCW. In the project of highhopping frequency synthesizer,we choose DDS and four PLL to up convertandaccording to therequirements of the specific indicators, we use FPGA to control DDS togenerate the high speedhoppingsignal. It is got by up convertingthe output of DDS andoutput offour PLL which has been controlled by switch.The spurious of signal afterup-conversion is mainy decided by DDS, phase noise is mainly decided by PLL.In theproject of pulse FMCW,weuse FPGA to control DDS to generatepulse FMCW. It is gotby up converting the output of DDS and output of one PLLResults show that:in the project of pulse FMCW,using FPGA to control DDS hasbeenachievedFMCW、PDWhen the control signal is high, the output of DDS isFMCW,else is PD.In the project of fast frequency hopping, results from test show that:：6.840~7.856GHz,spurs:<-60dBc,Phase Noise<-102dBc/Hz@10kHz.